Resorcinol-modified phenolic resin binder for reinforced plastics

ABSTRACT

A fire resistant resin for use as a binder in reinforced plastics and a resultant reinforced plastic includes the reaction product of (a) at least one resorcinol component selected from the group consisting of resorcinol and resorcinol formaldehyde novolak resin, and (b) a phenolic resole resin. The reaction may be achieved in the presence of an alkaline catalyst. 
     A method of making a fire resistant resin binder for reinforced plastics and the method of making such reinforced plastics including, (a) at least one resorcinol component selected from the group consisting of resorcinol and resorcinol formaldehyde novolak resin, and (b) a phenolic resole resin. The reaction may be achieved in the presence of an alkaline catalyst.

This application is a continuation of 07/307,414 filed Feb. 7, 1989, nowabandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a fire resistant resin for use as a binder inreinforced plastics and to such reinforced plastics as well as themethod of making such resins and plastics.

2. Description of the Prior Art

It has been known to employ reinforced plastic materials such asfiberglass, for example, in a wide variety of environments includingbuilding products, transportation uses such as automobiles, planes andboats, as well as many other uses, such as air ducts, panels, doors andelectrical conduits. The reinforcing material serves to enhance thestrength of the plastic materials and the binders secure the material inthe desired positions. A wide variety of reinforcing materials have beenemployed as reinforcing material. Examples of such materials are carbonfibers, glass fibers and flakes, glass or ceramic microspheres and awide variety of synthetic materials in various forms includingcontinuous fiber and chopped fiber.

Among the important considerations in resin binders used for suchpurposes are the desire to have effective resistance to both flame andsmoke development, as well as maintaining the desired mechanicalproperties at elevated temperatures.

It has been known to employ a condensation product of resorcinol andformaldehyde resins in combination with cement in such resins. See U.S.Pat. No. 3,663,720. See also, U.S. Pat. No. 3,502,610.

Building codes and regulatory agencies specify low smoke density valuesfor such thermosetting and thermoplastic materials that only a limitednumber of materials can be employed due to economic considerations.Further, increasingly tight restrictions have been imposed on emissionsof styrene, a chemical generally deemed necessary in the industry. Thisis so as styrene is currently under investigation as being a possiblecarcinogen. While phenolic resins have been suggested as a safealternative for fire retardant applications, one of the impediments togrowth of use of such composites is the reluctance of fabricators tohave the required acid catalyst present in the shop environment.

A serious problem with most fire-retardant resins is smoke emissions. Itis currently believed that a high percentage of fatalities and fire arecaused by smoke inhalation. Most fire retardant reinforced plastics tendto emit dense clouds of toxic and acutely irritating gases. Such smokeand gases can cause death or lung damage as a result of inhalation. Theyalso can obstruct vision, thereby interfering with escape to safety andefforts of fire fighters. Further, damage to facilities includingdelicate electronic equipment can occur.

Most phenolic laminating resins rely upon acid catalysts or hightemperature post-curing or both.

As formaldehyde has recently been classified as a carcinogen, one mustcarefully evaluate the level of paraformaldehyde disclosed in the priorart. It is important to reduce exposure of the laminating worker to alower level of formaldehyde emissions.

U.S. Pat. No. 4,403,066 discloses the use of liquid phenol-formaldehyderesoles in reinforced composites such as those reinforced by glassfiber. One of the difficulties with the system taught in this patent isthat it requires curing of the resin at an elevated temperature such asat about 80° to 150° C. and that it requires strongly acidic or alkalineconditions. See also, U.S. Pat. No. 4,433,129 which discloseshemi-formals of methylolated phenols including those made by reaction ofparaformaldehyde with liquid phenol to produce hemi-formals ofmethylolated phenols.

U.S. Pat. No. 4,433,119 discloses liquid compositions of a hemi-formalphenol or methylolated phenols with polymers such as phenol-formaldehyderesoles, phenol-formaldehyde, novolak, as well as other materials. Seealso U.S. Pat. No. 4,430,473.

U.S. Pat. No. 4,053,447 discloses a resorcinol-modified phenolic resinwhich is said to be curable without the addition of heat. Thisdisclosure requires the addition of paraformaldehyde powder to cure theresin mix.

It has been known to use resorcinol modified phenolic resins in themanufacture of glue laminated wooden structural members. Adaptation ofthis technology to reinforced plastics, has had limited success due tothe relatively high level of non-reactive solvents formerly necessary toachieve low viscosity in conventional resin systems. The high solventcontent of conventional "first generation resins" as well as the waterformed in the phenolic condensation reaction contribute to crazing,porosity and poor corrosion resistance experienced in earlier resinsystems.

In spite of the known prior art system, there remains a very real andsubstantial need for resin binder for reinforced plastics which willhave the desired flame and smoke development resistant characteristicswhile being curable at room temperature and easy to manufacture and use.

SUMMARY OF THE INVENTION

The present invention has met the above-described needs.

In the present invention, a fire resistant resin for use as a binder inreinforced plastics such as thermosetting plastics, is obtained from thereaction product of (a) at least one resorcinol component selected fromthe group consisting of resorcinol and resorcinol formaldehyde novolakresin, and (b) a phenolic resole resin with said reaction preferably butnot necessarily being achieved in the presence of an alkaline catalyst.The resin is curable at a temperature of about 16 to 160° C. in about 20to 0.06 hours, which will generally be at about 55° to 95° F. with aroom temperature cure for about 8 to 14 hours being most advantageous.

In addition, a methylene donor may be employed in the reaction so as toimprove processing and wet out of the reinforcing material andincreasing the cross-density thereby providing additional strength tothe reinforced plastic.

It is an object of the present invention to provide an improved phenolicresin which is usable as a binder in reinforced plastics and which hasexcellent resistance to flame development and extremely low smokedevelopment as well as excellent high temperature mechanical strength.

It is a further object of the present invention to provide such a resinwhich is curable at room temperature within a reasonable time.

It is a further object of the present invention to provide such a resinwhich eliminates the need to use paraformaldehyde as a curing agent andthereby retains less water and other volatile solvents which cancontribute to weakening of the composite plastic material, and reducesformaldehyde exposure.

It is a further object of the present invention to provide such aphenolic resin which has higher solids content and superior strength.

It is a further object of the present invention to provide such a resinwhich cures at an intermediate pH as well as with an acidic catalyst, ifdesired.

It is a further object of the present invention to provide such a resinwhich when exposed to flame not only facilitates lower level flamespread without requiring additives and lower levels of smoke emission,but provides less toxic smoke emissions.

It is a further object of the present invention to provide such resinsin reinforced plastics which possess improved tensile and flexuralproperties.

It is a further object of the present invention to provide such a resinwhich avoids the requirement that there be a strongly acidic or stronglyalkaline condition for curing and thereby avoids this source ofpotential damage to the reinforcing material.

It is a further object of the present invention to provide such a resinwhich does not contain any solvents which would damage the reinforcingmaterial.

These and other objects of the present invention will be more fullyunderstood from the following description of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The resin of the present invention is adapted to serve as an effectivebinder in reinforced plastics. The resin is a two part liquid-liquidpre-catalyzed system to which inert filler may be added as an extender,if desired. The filler, however, need not be employed in order toachieve the fire and smoke emission properties. The higher solidscontent does provide superior chemical resistance and lower porosity.Under the influence of flame contact or radiant heat, it resists flameand smoke development. The resin is preferably a reaction product of (a)at least one resorcinol component selected from the group consisting ofresorcinol and resorcinol formaldehyde novolak resin, and (b) a phenolicresole resin with said reaction preferably but not necessarily beingachieved in the presence of an alkaline catalyst.

A further advantage of the resin of the present invention over theacid-catalyzed phenolic resins is that it will not corrode tooling andyet is not so alkaline as to damage the glass mat.

One of the advantages of the resin is that it is curable to release atroom temperature within a reasonable time period. In general, it may becured at about 16 to 160° C. in about 20 to 0.06 hours. It will cure ina moderate pH on the order of about 6 to 10.

The resorcinol component may consist of about 32 to 80 weight percentresorcinol and preferably about 58 to 71 and about 5 to 12 weightpercent formaldehyde with about 5 to 11 weight percent being preferred.The resorcinol component may also have about 0.025 to 0.25 weightpercent and preferably about 0.03 to 0.07 weight percent of an organicacid solution such as p-toluene sulfonic acid or oxalic acid, forexample, in order to adjust the pH, or as a catalyst.

The phenolic resole has about 40 to 71 weight percent phenol andpreferably about 55 to 67 percent and about 20 to 52 percentparaformaldehyde and preferably about 35 to 43 percent.

One of the difficulties of the use of paraformaldehyde in the prior artsystems was the use of powder caused increased exposure of plantpersonnel to this potentially dangerous material. Among the advantagesof the present invention are the faster reacting time as theparaformaldehyde must dissolve and at least partially dissociate intoformaldehyde molecules before reaction with the phenolic. Also thepresent system is easier to use as the hardening agent is in liquid formand requires less mixing. Further, the present system produces a betterproduct as no solvent is required to dissolve the paraformaldehyde inorder that it can react.

The alkaline catalyst may be any suitable catalyst. It may be selectedfrom the group consisting of metallic hydroxides and metallic oxides andamines such as sodium hydroxide, ammonium hydroxide and potassiumhydroxide, for example.

In a preferred practice of the invention a further methylene donor isadded in order to reduce the mix viscosity and thereby improveprocessing and wet out of the reinforcing material. It also serves toincrease the cross-link density thereby providing added strength to thereinforced plastic. About 0.01 to 40 weight percent (based upon weightof the resin mix) and preferably about 12 to 21 weight percent of thealdehyde may be added to the reaction mix. The methylene donor may beany suitable methylene donor. Among the preferred materials are thoseselected from the group consisting of furfural, furfuryl alcohol,oxazolidine and acrolein as well as combinations thereof.

In making a reinforced plastic, the resin binder may be mixed with theplastic material such as a glass fiber reinforced plastic, e.g.,fiberglass in a conventional manner. The mixture may then be cured atroom temperature for about 12 to 24 hours in order to achieve thedesired bond between fibers and the plastic.

It will be appreciated that the method of making the fire resistantresin of the present invention involves reacting (a) at least oneresorcinol component selected from the group consisting of resorcinoland resorcinol formaldehyde novolak resin, and (b) a phenolic resoleresin. The reaction may advantageously be effected in the presence of analkaline catalyst and at room temperature.

In employing the method to reinforce a plastic, the plastic material isintimately admixed with the binder and then may be cured with theaddition of heat if desired to accelerate the action but mayadvantageously be cured at room temperature.

In order to verify the technical characteristics of the invention, aseries of tests were performed. These tests are reported in thefollowing examples.

In Examples 1 through 5 the resole component was made and in Examples 6through 11, the resorcinol component was made. Examples 12 through 19recite performance of the reaction and the properties of the resultingmaterials.

EXAMPLE 1

In this test 418.3 grams of a 90 percent solution of USP phenol, 3.7grams of zinc acetate dihydrate and 485.6 grams of 37 percentformaldehyde solution were added to a reaction flask equipped with astirrer, a condenser and a heating mantle. The reaction mass was heatedto 85° C. and a Dean Starke separator was connected to the condenser.50.0 grams of cyclohexane were added to the flask. Temperature wasadjusted to 72-73° C. and the reaction mass was refluxed, separating thewater azeotropically. 347 grams of water were collected and thecyclohexane was distilled off under vacuum. The resin was cooled to roomtemperature and decanted.

EXAMPLE 2

This test involved 1882.2 grams of a 90 percent solution of USP phenol,1187.8 grams of 91 percent paraformaldehyde and 16.9 grams of zincacetate dihydrate being added to a reaction flask equipped with astirrer, a condenser and a heating mantle. The reaction mass was heatedto 85° C. and maintained until a Gardner-Holdt bubble viscosity of Q-Rwas obtained. The resin was dehydrated under vacuum to 90° C., cooled toroom temperature and decanted.

EXAMPLE 3

In this test 658.8 grams of USP phenol were charged to a reaction flaskequipped with a stirrer, a condenser and a heating mantle. 34.3 grams of90 percent paraformaldehyde and 13.1 grams of a 45 percent solution ofpotassium hydroxide were added. The reaction mass was heated to 80° C.and maintained at that temperature. 308.4 grams of 91 percentparaformaldehyde were added in 9 increments over a two-hour period. Theresin was held at 80° C. until a Gardner-Holdt bubble viscosity of 19.3seconds at 23.0° C. was reached, then neutralized with 22.3 grams of a75 percent solution of toluene-xylene sulfonic acid. 2.0 grams of 45percent potassium hydroxide were added to adjust pH. The resin wascooled to room temperature and decanted.

EXAMPLE 4

In this test 76.2 pounds of a 90 percent solution of USP phenol wereadded to a reactor equipped with a stirrer, heating/cooling coil andcondenser. .68 pounds of zinc acetate dihydrate and 48.1 pounds of 91%paraformaldehyde were added with mixing. The reaction mass was heated to85° C. and temperature was maintained at that point until aGardner-Holdt bubble viscosity of "P" was obtained. The resin was thendehydrated under vacuum, cooled to room temperature and 45 pounds weredischarged. 19.2 pounds of furfural were mixed into the remainder anddischarged.

EXAMPLE 5

This test involved 76.2 pounds of a 90% solution of USP phenol wereadded to a reactor equipped with a stirrer, a heating/cooling coil and acondenser. 0.68 pounds of zinc acetate dihydrate and 48.1 pounds of 91percent paraformaldehyde being added while stirring. The reaction masswas heated to 85° C. and held at that temperature until a Gardner-Holdtbubble viscosity of 1-J was reached. The resin was dehydrated undervacuum to an endpoint viscosity of 30-50 seconds (Gardner-Holdt), cooledto room temperature and discharged.

EXAMPLE 6

In this test 1982.0 grams of Resorcinol, Technical Flake, were added toa reaction flask equipped with a stirrer, a condenser and a heatingmantle. 550 g. of de-ionized water and 131.1 grams of 37 percentformaldehyde were added to the flask. Heat was applied to 65° C. and anexotherm resulted. 305.9 grams of 37 percent formaldehyde were addedstreamwise after the exotherm had subsided. 5.4 grams of a 50 percentsolution of oxalic acid were added and the reaction mass temperature washeld above 100° C. for one-half hour. The resin was dehydrated atatmospheric pressure and then under vacuum to a temperature of 165° C.,then 427.1 grams of de-ionized water were added. The resin was cooled toroom temperature and decanted.

EXAMPLE 7

In this test 85.7 pounds of Resorcinol, Technical Flake, were charged toa reaction vessel equipped with a stirrer, a heating/cooling coil, and acondenser. 21.4 pounds of deionized water were added. 5.7 pounds of 37percent formaldehyde solution were added and heat was added until atemperature of 100° C. was reached. The reaction mass was stirred afterthe resorcinol dissolved. 13.2 pounds of 37 percent formaldehyde wereadded over a one-half hour period. 0.5 pound of 50 percent oxalic acidsolution was added and the reaction mass was held above 100° C. forone-half hour. The resin was dehydrated at atmospheric pressure, thenunder vacuum to 150° C., then 18.1 pounds of water were added. The resinwas cooled to room temperature and discharged.

EXAMPLE 8

This test involved 1982 grams of Resorcinol, Technical Flake beingcharged to a reaction vessel equipped with a stirrer, heating mantle anda condenser. 495.5 grams of distilled water and 218.5 grams of 37percent formaldehyde solution were added and mixed. Heat was applieduntil a temperature of 75° C. was reached, then the reaction exothermcaused the temperature to rise to 90° C. When peak temperature wasreached, 509.9 grams of 37 percent formaldehyde solution was addedslowly over a 11/2 hour period. Next, 18.4 grams of a 50 percent oxalicacid solution in water were added. Temperature was held above 100° C forone hour. The resin was heated and dehydrated at atmospheric pressure,then under vacuum to a temperature of 165° C. 852 grams of distilledwater and 1321.3 grams of resorcinol were added to the reaction flaskand mixed for one hour. The resin was cooled to room temperature anddischarged.

EXAMPLE 9

In this test 1982 grams of Resorcinol, Technical Flake, was charged to aglass reaction vessel equipped with a stirrer, condenser and heatingmangle. The resorcinol was melted and 13.6 grams of a 20 percentsolution of p-toluene sulfonic acid was added while mixing. 728.4 gramsof a 37 percent formaldehyde solution were added streamwise. Thereaction mass was held above 100° C. for one hour after the formaldehydeaddition was complete, then 321.3 grams of resorcinol were added. Thereaction mix was heated to dissolve the resorcinol and held for 1 hourabove 100° C. 161.8 grams of 50 percent sodium hydroxide were added. Theresin was cooled to room temperature and discharged.

EXAMPLE 10

In this test 56.5 pounds of Resorcinol, Technical Flake, were charged toa steel reactor equipped with a heating/cooling coil, a stirrer and acondenser. The resorcinol was melted and.4 pound of a 20 weight percentwater solution of p-toluene sulfonic acid was added to the reactor whilestirring. 20.8 pounds of a 37 percent formaldehyde solution were addedstreamwise to the reactor over a 11/2 hour period. The reaction mass washeld at 100-110° C. for one hour with mixing, then 37.7 pounds ofResorcinol, Technical Flake, were added to the vessel. Temperature wasmaintained at 80-100° C. for a 1/2 hour mixing period, then 5.8 poundsof a 50 percent solution of sodium hydroxide were added. The resin wascooled to room temperature and discharged.

EXAMPLE 11

This test involved 1101.1 grams of Resorcinol, Technical Flake beingadded to a reaction flask equipped with a stirrer, a condenser and aheating mantle. The resorcinol was heated to melting and 814 grams of a20 percent p-toluene sulfonic acid solution were added. 404.6 grams of a37 percent formaldehyde solution were added streamwise over a 45-minuteperiod and the reaction mass was maintained above 100° C. for one hour.734.2 grams of Resorcinol, Technical Flake, were added and mixed at80-100° C. for one-half hour. 112.0 grams of 50 percent sodium hydroxidewere added and mixed. The resin was cooled and decanted. To oneincrement, designated 11A, 5 parts per hundred resin (phr) of acetonewere added. To a second increment, designated as 11B, 5 phr of methanolwere added. A third increment was not modified.

EXAMPLE 12

Resins for Examples 2 and 6 were mixed with filler, solvents and bondingagents as per the table below and applied to chopped strand mat (whichis marketed by PPG Industries of Pittsburgh, Pa. under the tradedesignation PPG AKM) using hand layup techniques. Example 12A was heatedin a press at 85° C. for 10 minutes. Example 12B was maintained at roomtemperature. Mechanical properties were tested as per applicable ASTMprocedures. Glass content was approximately 25 weight percent. Resultsare listed below.

    ______________________________________                                                         Weight Percent                                                                A     B                                                      ______________________________________                                        Resin 2            36.2    36.2                                               Furfural           12.7    12.7                                               Resin 6            30.0    30.0                                               Mg(OH).sub.2        2.9     2.9                                               ATH                15.8    15.8                                               Aminosilane         2.4     2.4                                               NaOH                1.0     1.0                                               Tensile Strength, psi                                                                             10,816  11,364                                            Tensile Modulus, psi                                                                             754,220 779,240                                            Flexural Strength, psi                                                                            22,998  21,859                                            Flexural Modulus, psi                                                                            819,610 800,090                                            ______________________________________                                    

This Example shows a phenolic component at about 60 percent phenol and42 percent formaldehyde along with a resorcinol novolak at 77 percentresorcinol and 17 percent formaldehyde used to make the reinforcedplastic laminate. The results indicate good mechanical properties forthe laminates. The result also show that the properties were generallythe same whether the material was cured at room temperature or washeated to accelerate the cure.

EXAMPLE 13

Resins from Examples 4 and 7 were mixed with filler, solvents, catalystsand bonding promoters as per the previous example and applied to PPG AKMchopped strand mat using hand layup techniques. Glass content wasapproximately 25 weight percent. The amount of furfural and resin (7)was varied but the total ratio of methylene donor and acceptor wasmaintained. Mechanical properties were obtained with applicable ASTMtest methods and are listed below.

    ______________________________________                                                   A     B       C       D     E                                      ______________________________________                                        Furfural Content, phr                                                                      20      30      35    40    50                                   Tensile Strength,                                                                          10.7    11.7     9.4  12.2  10.7                                 psi × 10.sup.3                                                          Tensile Modulus,                                                                            0.76    0.79    0.61  0.85  0.71                                psi × 10.sup.6                                                          Flexural Strength,                                                                         21.0    23.1    20.7  25.6  23.8                                 psi × 10.sup.3                                                          Flexural Modulus,                                                                           0.75    0.85    0.79  0.89  0.86                                psi × 10.sup.6                                                          ______________________________________                                    

This Example illustrates a phenolic component at about 61 percent phenoland 38.5 percent formaldehyde. Furfural ratios were varied from 25 to 50parts per 100 parts of the phenolic component. The resorcinol novolakwas 79 percent resorcinol and 17.5 percent formaldehyde. This testshowed good results with varied amounts of furfural and resorcinolnovolak component.

EXAMPLE 14

Resins from Examples 4 and 7 were mixed with various fillers, solvents,catalysts and bonding promoters in the ratio from Example 11 and appliedto PPG AKM chopped strand mat using hand layup techniques (glass contentis approximately 25 weight percent). Samples were cured at roomtemperatures and testing using applicable ASTM procedures. Mechanicalproperties are listed below.

    ______________________________________                                                    A     B         C       D                                         ______________________________________                                        Filler        ATH     None      Talc  Kaolin                                  Tensile Strength,                                                                           13.1    11.0      10.9  9.6                                     psi × 10.sup.3                                                          Tensile Modulus,                                                                             0.94    0.78      0.79  0.62                                   psi × 10.sup.6                                                          Flexural Strength                                                                           22.7    21.6      19.9  23.8                                    psi × 10.sup.3                                                          Flexural Modulus,                                                                            0.73    0.67      0.67 0.92                                    psi × 10.sup.6                                                          ______________________________________                                    

These test illustrate examples of several different fillers i.e. ATH(hydrated alumina), kaolin (China clay) and talc or no filler can besatisfactorily employed in making laminates of the present invention.

EXAMPLE 15

Resins from Examples 3 and 8 were mixed with solvents, fillers,catalysts and bonding promoters as in earlier examples and applied toPPG AKM chopped strand mat at an approximate glass content of 25 weightpercent. Hand layup techniques were used and the samples were allowed tocure at room temperature. Mechanical testing was performed followingapplicable ASTM procedures. Results are listed below.

    ______________________________________                                                         Weight Percent                                               ______________________________________                                        Resin 3            41.5                                                       Furfural           16.6                                                       Resin 8            20.5                                                       Mg(OH).sub.2        3.3                                                       ATH                15.7                                                       Aminosilane         2.4                                                       NaOH                1.0                                                       Tensile Strength, psi × 10.sup.3                                                            8.6                                                       Tensile Modulus, psi × 10.sup.6                                                             0.81                                                      Flexural Strength, psi × 10.sup.3                                                          17.4                                                       Flexural Modulus, psi × 10.sup.6                                                            0.70                                                      ______________________________________                                    

This Example illustrates the activation and cure of a conventionalphenolic resole (non-Bender catalyzed) containing about 63.5 percentphenol and 33 percent formaldehyde by addition of a resorcinol novolakcontaining about 74.3 percent resorcinol and 16.4 percent formaldehydealong with the addition of an aldehyde source, furfural, to make alaminate with reasonably satisfactory mechanical properties when curedat room temperature. These tests demonstrate that the use of resorcinolor a resorcinol novolak has broader applications than the specific typeof resole resin employed in the other examples.

EXAMPLE 16

A resole resin commercially available from Koppers Company, Inc., ofPittsburgh, Pa., under the trade designation B-505-10, and a resin fromExample 8 were mixed with solvents, fillers, catalysts and bondingpromoters and applied using hand layup techniques to PPG AKM choppedstrand mat at a glass content of approximately 25 weight percent.Mechanical properties were evaluated using applicable ASTM testprocedures and are listed below.

    ______________________________________                                                           Weight Percent                                                                A     B                                                    ______________________________________                                        Resole               34.6    33.9                                             Furfural             13.8    13.5                                             Resin 8              29.7    29.1                                             Mg(OH).sub.2          2.8     2.7                                             ATH                  15.8    15.4                                             Aminosilane           2.1     2.1                                             NaOH                  1.0     2.9                                             Tensile Strength, psi × 10.sup.3                                                             10.6     8.6                                             Tensile Modulus, psi × 10.sup.6                                                               0.84    0.87                                            Flexural Strength, psi × 10.sup.3                                                            18.0    16.3                                             Flexural Modulus, psi × 10.sup.6                                                              0.64    0.63                                            NBS Smoke Chamber                                                             D max. Flaming Mode  37      --                                               Smoldering Mode      15      --                                               ______________________________________                                    

The tests of Example 16 were very similar in objective to those ofExample 15. A different resole, i.e. Koppers phenolic foam resoleavailable under the trade designation B-505-10 was cured by the additionof a resorcinol novolak and a methylene donor, furfural under mildlyalkaline conditions to produce a satisfactory laminate at roomtemperature.

EXAMPLE 17

Resins for Examples 5 and 11 were mixed with solvents, fillers,catalysts and bonding promoters and applied to PPG AKM chopped strandmat using hand layup technique. Glass content was approximately 25weight percent. Mechanical results were obtained using applicable ASTMtest methods and are listed below.

    ______________________________________                                                        Weight Percent                                                                A       B       C                                             ______________________________________                                        Resin 5           34.2      34.6    34.6                                      Resin             (11)      (11A)   (11B)                                     Level             30.6      29.9    29.9                                      Furfural          13.7      13.9    13.9                                      Mg(OH).sub.2       2.7       2.7     2.7                                      ATH               15.7      15.7    15.7                                      Aminosilane        2.4       2.4     2.4                                      NaOH               1.0       1.0     1.0                                      Tensile Strength, psi × 10.sup.3                                                          13.3      10.8    10.6                                      Tensile Modulus, psi × 10.sup.6                                                            0.99      0.73    0.78                                     Flexural Strength, psi × 10.sup.3                                                         20.0      16.7    19.1                                      Flexural Modulus, psi × 10.sup.6                                                           0.68      0.60    0.64                                     Limiting Oxygen Index                                                                           54        48      49                                        NBS Smoke Chamber                                                             D max. Flaming Mode                                                                             28        12      17                                        Smoldering Mode   9         5       8                                         ______________________________________                                    

This Example establishes that satisfactory laminates may be made withresorcinol novolaks diluted with solvents to improve processabilitywithout having a negative effect on smoke emissions. A resole withphenol, furfural and formaldehyde in the preferred range and aresorcinol novolak in the preferred ranges were employed.

EXAMPLE 18

Resins from Examples 5 and 10 were mixed with fillers, solvents,catalysts and bonding promoters and applied using hand layup techniquesto a variety of chopped strand mats as listed below. Glass content wasapproximately 35 weight percent. Mechanical testing was done followingapplicable ASTM procedures. Results are listed below.

    __________________________________________________________________________    Glass   Owens Owens              Owens                                        Manufacturer                                                                          Corning                                                                             Corning                                                                             Certainteed                                                                         Scandinavian                                                                         Corning                                      __________________________________________________________________________    Type    M902x23A                                                                            M-710 M-127 MK10B  M-711                                        Tensile St.,                                                                          14.2  14.4  14.9  14.4   13.1                                         psi × 10.sup.3                                                          Tensile Mod.,                                                                          0.72  0.99  0.86  0.81   0.84                                        psi × 10.sup.6                                                          Flexural St.,                                                                         32.3  30.4  31.0  26.8   29.4                                         psi × 10.sup.3                                                          Flexural Mod.,                                                                         1.15  1.09  1.11  0.99   0.97                                        psi × 10.sup.6                                                          __________________________________________________________________________

These tests show that the invention was effective in the preferredranges with a variety of brands of fiberglass reinforcement.

EXAMPLE 19

Resins from Examples 5 and 10 were mixed with solvents, fillers,catalysts and bonding promoters and applied to Certainteed M-127®chopped strand mat, faced with C-glass veil, using hand layuptechniques. Glass content was approximately 35 weight percent.Mechanical properties were evaluated by applicable ASTM test proceduresand are listed below. Fillers were added at 12.5 and 20 weight percentlevels.

    ______________________________________                                                           A     B                                                    ______________________________________                                        Filler, weight percent                                                                             12.5    20.0                                             Tensile Strength, psi × 10.sup.3                                                             16.5    17.6                                             Tensile Modulus, psi × 10.sup.6                                                               0.95    1.39                                            Flexural Strength, psi × 10.sup.3                                                            25.8    24.9                                             Flexural Modulus, psi × 10.sup.6                                                              1.18    1.13                                            D max. Flaming Mode  22      17                                               ______________________________________                                    

Example 19 shows laminates using the preferred ratio of components andtwo levels of a different filler i.e. barium sulfate as well as adifferent type of veil. This illustrates as well the numerous areas ofpotential improvements over the prior art with minor modifications whichone skilled in the art may employ.

It will be appreciated that desired additional ingredients may beemployed in the resin and resultant composite plastic of the presentinvention if desired. For example, fillers, if desired, such as woodflower, barium sulfate, hydrated alumina, silicates, kaolin, talc,walnut shell flower, glass beads, ceramic and, for example, carbon maybe employed in a manner known to those skilled in the art. While suchfillers may be employed in order to reduce costs and contribute todimensional stability, they are not needed to provide flame and smokeretardation. In addition, should it be desired, pigments may beemployed. Accelerators and other additives known to those skilled in theart may be employed.

While for simplicity of disclosure herein, reference has been tofiberglass as the reinforced plastic, it will be appreciated that otherreinforced plastics whether or not reinforced by glass or syntheticfibers may be used beneficially with the resinous binder of the presentinvention. Included in such materials are polyvinyl choloridepolyethylene, polypropylene, polyester urethane and epoxies.

It will be appreciated, therefore, that the present invention providesan efficient resinous binder and method of using the same in creatingreinforced plastics having improved properties. All of this isaccomplished in a simple and economical manner which permits the use ofroom temperature curing and has the desired flame and smoke resistingcharacteristics. All of this is done in such a manner as to eliminatethe disadvantageous characteristics of the use of paraformaldehyde as acuring agent.

It will be appreciated that the resins and reinforced plastics of thepresent invention are usable in a wide range of environments wherereinforced plastics are employed.

While the invention facilitates the advantageous use of alkalinecatalysts, the invention is not so limited. If desired, for example,acid catalysts may be used.

Whereas particular embodiments of the invention have been describedabove for purposes of illustration, it will be appreciated by thoseskilled in the art that numerous variations of the details may be madewithout departing from the invention as described in the appendedclaims.

I claim:
 1. A fire resistant resin for use as a binder in reinforced plastics comprising the reaction product of:(a) at least one resorcinol component selected from the group consisting of resorcinol and resorcinol formaldehyde novolak resin, wherein said resorcinol formaldehyde novolak resin comprises the reaction product of an aldehyde and resorcinol in the presence of an acidic catalyst; and (b) a phenolic resol resin comprising the reaction product of a phenol and either formaldehyde or paraformaldehyde, wherein said paraformaldehyde first dissolves and at least partially dissociates into formaldehyde before reacting with said phenol.
 2. The fire resistant resin of claim 1 including said reaction product resulting from the reaction of said resorcinol component and said phenolic resole resin being achieved in the presence of an alkaline catalyst.
 3. The fire resistant resin of claim 1 includingsaid resin being characterized by the property of having been cured to release at a temperature of about 16° to 160° C. in about 20 to 0.06 hours.
 4. The fire resistant resin of claim 3 includingsaid resin being characterized by the property of having been cured to release at room temperature.
 5. The fire resistant resin of claim 3 includingsaid binder having a pH of about 6 to
 10. 6. The fire resistant resin of claim 3 includingemploying about 0.01 to 40 weight percent based on weight of the resin mix of a methylene donor in said reaction.
 7. The fire resistant resin of claim 6 includingsaid methylene donor being selected from the group consisting of furfural, furfuryl alcohol, oxazolidine, acrolein and combinations thereof.
 8. The fire resistant resin of claim 3 includingsaid resorcinol component having about 32 to 80 weight percent resorcinol and about 5 to 12 weight percent formaldehyde.
 9. The fire resistant resin of claim 8 includingsaid resorcinol component having about 0.025 to 0.25 weight percent of said acidic catalyst.
 10. The fire resistant resin of claim 9 includingsaid phenolic resole having about 40 to 71 weight percent phenol and about 20 to 52 percent paraformaldehyde.
 11. The fire resistant resin of claim 2 includingsaid alkaline catalyst being selected from the group consisting of metallic hydroxides, metallic oxides and amines.
 12. A reinforced plastic fire retardant article comprisingan admixture of a reinforcing material being a binder with said reinforced plastic material, said binder being composed of the resin which is the reaction product of:(a) at least one resorcinol component selected from the group consisting of resorcinol and resorcinol formaldehyde novolak resin, wherein said resorcinol formaldehyde novolak resin comprises the reaction product of an aldehyde and resorcinol in the presence of an acidic catalyst; and (b) a phenolic resole resin comprising the reaction product of a phenol and either formaldehyde or paraformaldehyde, wherein said paraformaldehyde first dissolves and at least partially dissociates into formaldehyde before reacting with said phenol.
 13. The fire retardant article of claim 12 including said reaction product resulting from the reaction of said resorcinol component and said phenolic resole resin being achieved in the presence of an alkaline catalyst.
 14. The fire retardant article of claim 12 includingsaid reinforcing material being fiberglass.
 15. The fire retardant article of claim 14 includingsaid resin being characterized by the property of being curable to release at a temperature of about 16 to 160° C. in about 20 to 0.06 hours.
 16. The fire retardant article of claim 15 includingsaid binder having a pH of about 6 to
 10. 17. The fire retardant article of claim 15 includingemploying about 0.01 to 40 weight percent based on weight of the resin mix of a methylene donor in said reaction.
 18. The fire retardant article of claim 15 includingemploying about 12 to 21 weight percent based on weight of the resin mix of a methylene donor in said reaction.
 19. The fire retardant article of claim 15 includingsaid resorcinol component having about 32 to 80 weight percent resorcinol and about 5 to 12 percent formaldehyde.
 20. The fire retardant article of claim 19 includingsaid resorcinol component having about 58 to 71 weight percent resorcinol and about 4 to 7 weight percent formaldehyde.
 21. The fire retardant article of claim 19 includingsaid resorcinol component having about 0.025 to 0.25 weight percent of said acidic catalyst.
 22. The fire retardant article of claim 19 includingsaid phenolic resole having about 40 to 71 weight percent phenol and about 20 to 52 percent paraformaldehyde.
 23. The fire retardant article of claim 22 includingsaid phenolic resole having about 55 to 67 weight percent phenol and about 35 to 43 weight percent paraformaldehyde.
 24. The fire retardant article of claim 13 includingsaid alkaline catalyst being selected from the group consisting of sodium hydroxide, ammonium hydroxide and amines. 